All experimental days will be exactly the same. All volunteers will attend the clinical research and trial unit in a fasted state. Prior to test administration, baseline vascular function will be assessed and biological samples taken by a trained and qualified research nurse. Subsequently, assessments will be repeated at times corresponding to anticipated peak plasma concentration of the flavonoid of interest.

Dietary Supplement: Flavanone - supplement

acute single optimal dose

Other: Flavanone - food

acute single dose

Other: Flavanone - placebo

acute single dose (flavanone free)

Experimental: Intervention group B: isoflavones

All experimental days will be exactly the same. All volunteers will attend the clinical research and trial unit in a fasted state. Prior to test administration, baseline vascular function will be assessed and biological samples taken by a trained and qualified research nurse. Subsequently, assessments will be repeated at times corresponding to anticipated peak plasma concentration of the flavonoid of interest.

Dietary Supplement: Isoflavone - supplement

acute single optimal dose

Other: Isoflavone - food

acute single optimal dose

Other: Isoflavone - placebo

acute single dose (isoflavone free)

Dietary Supplement: Isoflavone - metabolite supplement

acute single optimal dose of commercial product

Experimental: Intervention group C: Flavan-3-ols

All experimental days will be exactly the same. All volunteers will attend the clinical research and trial unit in a fasted state. Prior to test administration, baseline vascular function will be assessed and biological samples taken by a trained and qualified research nurse. Subsequently, assessments will be repeated at times corresponding to anticipated peak plasma concentration of the flavonoid of interest.

Dietary Supplement: Flavan-3-ol - supplement

acute single optimal dose

Other: Flavan-3-ol - food

acute single optimal dose

Other: Flavan-3-ol - placebo

acute single dose (flavan-3-ol free)

Experimental: Intervention group D: Anthocyanins

All experimental days will be exactly the same. All volunteers will attend the clinical research and trial unit in a fasted state. Prior to test administration, baseline vascular function will be assessed and biological samples taken by a trained and qualified research nurse. Subsequently, assessments will be repeated at times corresponding to anticipated peak plasma concentration of the flavonoid of interest.

Dietary Supplement: Anthocyanin - supplement

acute single optimal dose

Other: Anthocyanin - food

acute single optimal dose

Other: Anthocyanin - placebo

acute single dose (anthocyanin free)

Detailed Description:

The study population will be healthy males (aged 50-75 years) at elevated risk of cardiovascular (CV) disease.

A target of 60 participants will be required to complete the study and a total of 70 subjects will be targeted (n=70 subjects * ~85% anticipated completion rate = 60 subjects to complete the study).

Accordingly, subjects will be randomised to one of the four flavonoid study groups ((i) to (iv) outlined above), and then will consume each of the following treatments in random order:

dietary flavonoid + placebo supplement

placebo food + commercially available/produced flavonoid supplement

placebo food + placebo supplement

Additionally, an isoflavone metabolite will be fed to establish potential vascular effects.

Each sub-class will be assessed separately and a 1 week wash-out period between treatments will be observed.

At each assessment visit, vascular function will be assessed pre- and post-intervention, with subsequent assessments made to coincide with anticipated peak plasma concentrations.

Dietary intake will be monitored during the study and participants will be required to adhere to a range of dietary and lifestyle restrictions within 3 days of each assessment to reduce potential confounding of the data assessment of interest.

A standard battery of vascular function tests will be performed on all intervention groups, with each assessment visit performed in an identical manner.

Unsatisfactory biochemical, haematological or urinary assessment at screening, indicating abnormal; renal or liver function, full blood profile, impaired glucose handling, deranged lipids or measurements considered to be counter indicative of the study by the clinical advisor

Contacts and Locations

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study.
To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below.
For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01530893